The present invention relates to the field of dispensers. More particularly, the invention relates to a paste dispenser, wherein a dispenser head may be actuated and paste may be dispensed in metered fashion with the use of only one hand. A rigid container for the paste is employed within which a unit is displaceable based on a pressure differential between the interior and exterior of a pumping chamber.
Toothpaste is a well known dentifrice that effectively prevents tooth decay. Toothpaste is generally contained in a collapsible tube and is applied to a toothbrush to facilitate the cleaning of teeth. Several drawbacks are associated with the usage of a conventional tube for the dispensing of toothpaste therefrom. Since toothpaste is dispensed by squeezing the tube, a significant amount of toothpaste remains in the tube due to the inability of deforming the tube to such an extent so as to allow for the removal of the entire amount of the semi-fluid material. Also, an uncontrollable amount of toothpaste may be applied to a toothbrush, often resulting in unnecessary waste. At times, the cap of the toothpaste tube is misplaced and a significant amount of toothpaste is liable to dry, proximate to the aperture through which the toothpaste is released. Furthermore, the application of toothpaste to a toothbrush is an awkward procedure, in which two hands are generally needed for accurate and speedy dispensing.
Numerous prior art toothpaste dispensers, which overcome some of the aforementioned drawbacks, are known. For example, GB 2150105 discloses a dispenser that incorporates a means for mounting and moving a collapsible container relative to an evacuating means. Upon insertion of a toothbrush into a recess, a closure arm bears against an dispenser head lever, thereby moving the container a predetermined distance by the interengagement of a pinion and rack. DE 19808864 discloses an apparatus that includes a slide which is horizontally displaced upon insertion of a toothbrush, whereby a protrusion carried by the slide engages another member which uncovers the aperture through which toothpaste is dispensed. The slide is also provided with teeth which are engageable with a ratchet-toothed gear, the rotation of which causes rollers to squeeze a toothpaste tube. DE 3417312 is directed to a metering device which comprises a stationary housing part and a movable housing part. By pivoting the movable housing part relative to the stationary housing part, an actuating element is pressurized so that the required quantity of the substance to be metered is dispensed. U.S. Pat. No. 5,975,362 discloses a dispenser which comprises a rotatable power source for rotating a pair of pinch rollers, which move along a toothpaste tube to collapse a portion of the tube to thereby dispense toothpaste. All of these references are characterized by having a relatively large number of moving parts, resulting in a higher cost and a higher chance of malfunction.
U.S. Pat. No. 3,088,636 discloses a dispenser for a fluent mass, which is discharged therefrom as the effective volume of the container forwardly of a piston means is decreased, after which the volume is increased to create a partial vacuum, thereby allowing atmospheric pressure rearwardly of the piston means to act thereon and to move it forwardly in the container, so that the effective volume of the container is again decreased.
U.S. Pat. No. 3,268,123 provides a similar dispenser, without application of pressure to the fluent mass during the initial phase of decreasing the effective volume forward of the piston means. The device comprises means for resisting movement of the piston means in a rearward direction while permitting its movement in a forward direction within the container. Similar arrangements are taught in e.g. U.S. Pat. Nos. 4,978,037, 4,991,744 and 6,047,862.
Dispensers having a flexible membrane, which is flexed by means of a dispenser head following the depressing thereof, so that the membrane is longitudinally displaced in a rearward direction to allow for the decreasing of the effective volume of the container, are taught in e.g. U.S. Pat. No. 4,691,847, GB 2,161,222, U.S. Pat. No. 4,776,496, U.S. Pat. Nos. 4,936,493, 4,962,851. Paste is dispensed from the dispensers of the aforementioned citations with the use of two hands, and is at times an awkward procedure.
FIG. 1 schematically illustrates a toothpaste dispenser described in U.S. Pat. No. 6,047,862. In FIG. 1 said dispenser is generally designated by 5 and is provided with reservoir 2, pump head 3 and dispensing orifice 7. Closure 8 generally covers nozzle 7, and is separated therefrom during the dispensing of toothpaste. Reservoir 2 is cylindrical and contains toothpaste within pumping chamber 6, defined by the region between pressurizing means 9 and a follower piston, generally designated by 15. Distal end 10 of the dispenser which may have a larger outer diameter than container 2, is adapted to admit air to the distal end of unit 15. Toothpaste does not come in contact with air, and therefore cannot dry.
An exploded drawing of an exemplary incrementally displaceable unit 15 is shown in FIG. 2. Unit 15 comprises three elements: piston 18, clamp module 27 and disc 32. Piston 18 is described in detail in U.S. Pat. No. 4,978,037, and is provided with a plurality of circumferential fields 19 and 20, wherein each adjacent field is separated by a radially oriented groove 22 and 23, respectively. Each field 20 is disposed closer to the outer wall of centrally disposed seat 13 than a corresponding field 19. The piston is provided with distal lip 25 and proximate lip 26. Lips 25 and 26 have an outer diameter substantially equal to the inner wall of a tubular paste container and serve as a seal.
By means of clamp module 27, unit 15 is displaceable in only one direction, i.e. towards dispenser head 3, after dispenser 5 has been loaded with toothpaste. Clamp module 27 is shaped in the form of a star, with radially oriented prongs 29 interspersed between circumferential spacers 30, and is made of spring steel. The center of clamp module 27 is formed with aperture 31 having a diameter substantially equal to the outer wall of seat 13. Aperture 31 allows the clamp module to be pressed fit with diaphragm 18, such that each spacer 30 contacts distal lip distal lip 25. The diameter spanned by the ends of prongs 29 is slightly larger than the inner wall of container 2, and since the prongs are angled in a direction away from distal lip 25, displacement of unit 15 in a direction away from dispenser head 3 is prevented.
Disc 32 is the means by which unit 15 is displaced, as will be described hereinafter. Disc 32 is planar and circular, and is provided with peg 34 protruding from the proximate side thereof. Peg 34 is insertable within seat 13, so that disc 32 is carried by piston 18 as the latter is displaced.
All the methods described above have not yet provided satisfactory solutions to the problem of providing an inexpensive toothpaste dispenser with a minimal number of moving parts, which can apply toothpaste to a toothbrush by the use of only one hand and capable of dispensing a metered amount of toothpaste.
It is an object of the present invention to provide a toothpaste dispenser which can apply toothpaste to a toothbrush by the use of only one hand.
It is an additional object of the present invention to provide a toothpaste dispenser which is capable of dispensing a metered amount of toothpaste.
It is an additional object of the present invention to provide a toothpaste dispenser which is inexpensive with a minimal number of moving parts.
It is a further object of the present invention to provide a toothpaste dispenser wherein the toothpaste cannot dry.
Other objects and advantages of the invention will become apparent as the description proceeds.
The present invention relates to an improved dispenser for pastes comprising:
a) a paste container having a wall,
b) an elastic means having a base configuration, being deformable by application of a force thereto and elastically returning to said base configuration when said application of a force is discontinued,
c) a displaceable element,
d) said wall, elastic means and displaceable element defining a variable volume paste chamber,
e) a dispenser nozzle communicating with said chamber for dispensing paste therefrom,
f) said displaceable element being displaced by room pressure, as a result of a reduced pressure in said paste chamber, towards said elastic means upon the return of said elastic means to said base configuration,
g) an actuating member, accessible from outside the container and displaceable from an inactive to an active position,
h) means for applying a force to said elastic means to deform said elastic means, in such a way as to reduce the volume of said chamber, thereby causing said paste to be dispensed through said dispenser nozzle, when said actuating member is displaced from the inactive to the active position, and
i) a kinematism for kinematically connecting said actuating member to said means for applying a force to said elastic means to deform said elastic means, when said actuating means is displaced to its active position, and for allowing said elastic means elastically to return to said base configuration thereof when said actuating means is returned to its inactive position.
Preferably:
1) the wall of the paste container is tubular and the elastic means and the displaceable element are located at its opposite ends;
2) the actuating means comprise a swinging member that can be manually swung from the inactive to the active position by applying a force to it, more preferably through a toothbrush, and is provided with spring means to return it to the inactive position when the force is no longer applied to it;
3) the dispenser nozzle is normally in an inoperative position in which it does not communicate with the paste chamber and is displaceable, upon actuation of the actuating means, to an operative position in which it communicates with the paste chamber to allow dispensation of the paste therefrom;
4) the dispenser nozzle is operatively connected to the actuating means and to the elastic means and is a part of the said kinematism, whereby it is displaced to its operative position concurrently with the application of a force to the said elastic means.
5) a housing, more preferably a rigid, fixed housing, is provided for reciving and supporting a paste dispenser at a time, each paste dispenser being more preferably engageable with said housing, e.g. by means of projections engaging recesses provided in said housing, and protruding therefrom as far as necessary for the actuating means to be operated and for the paste to be received from the dispensing nozzle;
6) the displaceable element is a piston.
The displaceable element actually becomes displaced by increments, corresponding to the amount of paste discharged each time, though it has no such mechanical limitation, and because of this can be said to be incrementally displaceable.
As referred to herein, the xe2x80x9cproximatexe2x80x9d part of the dispenser is the one close to the dispenser head from which the paste is dispensed and the xe2x80x9cdistalxe2x80x9d part is the one distant from the dispenser head. In use, the proximate part is generally the lower one and the distal part is the upper one. xe2x80x9cInwardsxe2x80x9d means in a direction towards the interior of the container, xe2x80x9coutwardsxe2x80x9d means in a direction towards the exterior of the container, xe2x80x9clongitudinalxe2x80x9d is in a direction parallel to the length of the container, and xe2x80x9clateralxe2x80x9d is in a direction perpendicular to a longitudinal direction.
In an embodiment, the container is permanently attached to the housing. In another embodiment, the container is releasably attachable to the housing.
The container is preferably attached to the housing by means of protrusions formed on the at least one outer wall of the container, said protrusions being insertable within similarly shaped tracks formed within the housing. Preferably, the protrusions extend longitudinally downwards along the container. Alternatively, the container can be attached to the housing by means of threading.
The housing is preferably provided with an air inlet, the incrementally displaceable unit being displaceable in a proximate direction due to a pressure differential between the interior and exterior of the pumping chamber of the dispenser, the pumping chamber achieving a partial vacuum upon discharge of paste from the pump chamber.